Urological operations are commonly performed in the lithotomy position. A rare, but serious, complication is the compartment syndrome, which can result in neurovascular damage and permanent disability or limb loss. We describe two cases of compartment syndrome. One arose after transurethral resection of the prostate, and the other after an operation to change a transsexual patient from man to woman. The literature is reviewed, and the causes of the syndrome and possible ways of preventing serious consequences to the patients affected are discussed.